Among seatbelt devices, there are those that wind up a webbing by using a motor. These seatbelt devices control a retractor so that a passenger is not restrained unnecessarily due to wind-up of the webbing by the motor. Specific control of such a retractor includes, for example as described in Patent Document 1, a step of tensioning the webbing by driving the motor in a wind-up direction of the webbing, a step of automatically monitoring a specific release criteria in order to release the webbing after completing application of tension to the webbing, and a step of starting drive of the motor for a short time in a pull-in direction of the webbing in order to release a locking member when the release criteria is satisfied.